Allow `iced_wgpu` to render to any `TextureView`

3 files changed, 92 insertions, 40 deletions

diff --git a/native/src/window.rs b/native/src/window.rs
index db9226dc..4dcae62f 100644
--- a/native/src/window.rs
+++ b/native/src/window.rs
@@ -1,6 +1,6 @@
 //! Build window-based GUI applications.
+mod backend;
 mod event;
-mod renderer;
 
+pub use backend::Backend;
 pub use event::Event;
-pub use renderer::{Renderer, Target};
diff --git a/native/src/window/backend.rs b/native/src/window/backend.rs
new file mode 100644
index 00000000..690dbdab
--- /dev/null
+++ b/native/src/window/backend.rs
@@ -0,0 +1,55 @@
+use crate::MouseCursor;
+
+use raw_window_handle::HasRawWindowHandle;
+
+/// A graphics backend that can render to windows.
+pub trait Backend: Sized {
+    /// The settings of the backend.
+    type Settings: Default;
+
+    /// The iced renderer of the backend.
+    type Renderer: crate::Renderer;
+
+    /// The surface of the backend.
+    type Surface;
+
+    /// The swap chain of the backend.
+    type SwapChain;
+
+    /// Creates a new [`Backend`] and an associated iced renderer.
+    ///
+    /// [`Backend`]: trait.Backend.html
+    fn new(settings: Self::Settings) -> (Self, Self::Renderer);
+
+    /// Crates a new [`Surface`] for the given window.
+    ///
+    /// [`Surface`]: #associatedtype.Surface
+    fn create_surface<W: HasRawWindowHandle>(
+        &mut self,
+        window: &W,
+    ) -> Self::Surface;
+
+    /// Crates a new [`SwapChain`] for the given [`Surface`].
+    ///
+    /// [`SwapChain`]: #associatedtype.SwapChain
+    /// [`Surface`]: #associatedtype.Surface
+    fn create_swap_chain(
+        &mut self,
+        surface: &Self::Surface,
+        width: u32,
+        height: u32,
+        scale_factor: f64,
+    ) -> Self::SwapChain;
+
+    /// Draws the output primitives to the next frame of the given [`SwapChain`].
+    ///
+    /// [`SwapChain`]: #associatedtype.SwapChain
+    /// [`Surface`]: #associatedtype.Surface
+    fn draw<T: AsRef<str>>(
+        &mut self,
+        renderer: &mut Self::Renderer,
+        swap_chain: &mut Self::SwapChain,
+        output: &<Self::Renderer as crate::Renderer>::Output,
+        overlay: &[T],
+    ) -> MouseCursor;
+}
diff --git a/native/src/window/renderer.rs b/native/src/window/renderer.rs
index a3cbb8ce..b0cc0134 100644
--- a/native/src/window/renderer.rs
+++ b/native/src/window/renderer.rs
@@ -2,57 +2,54 @@ use crate::MouseCursor;
 
 use raw_window_handle::HasRawWindowHandle;
 
-/// A renderer that can target windows.
-pub trait Renderer: crate::Renderer + Sized {
-    /// The settings of the renderer.
+/// A graphics backend that can render to windows.
+pub trait Backend: Sized {
+    /// The settings of the backend.
     type Settings: Default;
 
-    /// The type of target.
-    type Target: Target<Renderer = Self>;
+    /// The iced renderer of the backend.
+    type Renderer: crate::Renderer;
 
-    /// Creates a new window [`Renderer`].
+    /// The surface of the backend.
+    type Surface;
+
+    /// The target of the backend.
+    type Target;
+
+    /// Creates a new [`Gpu`] and an associated iced renderer.
     ///
-    /// [`Renderer`]: trait.Renderer.html
-    fn new(settings: Self::Settings) -> Self;
+    /// [`Gpu`]: trait.Gpu.html
+    fn new(settings: Self::Settings) -> (Self, Self::Renderer);
 
-    /// Performs the drawing operations described in the output on the given
-    /// target.
+    /// Crates a new [`Surface`] for the given window.
     ///
-    /// The overlay can be a bunch of debug text logs. It should be rendered on
-    /// top of the GUI on most scenarios.
-    fn draw<T: AsRef<str>>(
+    /// [`Surface`]: #associatedtype.Surface
+    fn create_surface<W: HasRawWindowHandle>(
         &mut self,
-        output: &Self::Output,
-        overlay: &[T],
-        target: &mut Self::Target,
-    ) -> MouseCursor;
-}
-
-/// A rendering target.
-pub trait Target {
-    /// The renderer of this target.
-    type Renderer;
+        window: &W,
+    ) -> Self::Surface;
 
-    /// Creates a new rendering [`Target`] from the given window handle, width,
-    /// height and dpi factor.
+    /// Crates a new [`Target`] for the given [`Surface`].
     ///
-    /// [`Target`]: trait.Target.html
-    fn new<W: HasRawWindowHandle>(
-        window: &W,
+    /// [`Target`]: #associatedtype.Target
+    /// [`Surface`]: #associatedtype.Surface
+    fn create_target(
+        &mut self,
+        surface: &Self::Surface,
         width: u32,
         height: u32,
         scale_factor: f64,
-        renderer: &Self::Renderer,
-    ) -> Self;
+    ) -> Self::Target;
 
-    /// Resizes the current [`Target`].
+    /// Draws the output primitives to the given [`Target`].
     ///
-    /// [`Target`]: trait.Target.html
-    fn resize(
+    /// [`Target`]: #associatedtype.Target
+    /// [`Surface`]: #associatedtype.Surface
+    fn draw<T: AsRef<str>>(
         &mut self,
-        width: u32,
-        height: u32,
-        scale_factor: f64,
-        renderer: &Self::Renderer,
-    );
+        renderer: &mut Self::Renderer,
+        target: &mut Self::Target,
+        output: &<Self::Renderer as crate::Renderer>::Output,
+        overlay: &[T],
+    ) -> MouseCursor;
 }